FILE 2013: North Korean leader Kim Jong-un visits a Mushroom Farm in Pyongyang. There is speculation about the young leader's health because he has not made a public appearance in over a month. (REUTERS/KCNA)

North Korea's mysterious leader Kim Jong-un has not been seen in public for 34 days, sparking a wide range of speculation -- including that the head of one of the world's most secretive countries is ailing or has been removed in a secret coup.